Electric water heater of the nonstorage type



Allg. 20, 192.9.v qSTUBBS ET AL v1,712.5.;,683

ELECTRIC WATER HEATER OF'THE NONSTORAGE TYPE Aug. 20, 1929. w. STUBS ET AL 1,725,683

I `ELECTRIC WATER HEATER OF THE NONSTORAGE TYPE Patented Aug. 20, 1929. i i

UNITED STATES PATENT OFFICE.

WALTER STUBBS AND HORACE STUBBS, OF EPPING, NEW SOUTH WALES, AUSTRALIA.

ELECTRIC WATER HEATER Application filed August 28, 1924, Serial No.

Hitherto electric water heaters for heating large quantities of water, e. g., for baths, etc., have been expensive to manufacture and owing to the consumpt-ion ot' electric current and leakage they have also been costly to maintain.

The main objects of the present invention are to simplify the construction and at the same time provide an elticient water heater.

Further objects are to so construct and arrangs the parts ot' the heater that the electric circuit through the heating element cannot be completed until the heating element is entirely submerged, to reduce the leakage to earth to a minimum and to eliminate all danger of any exposed portions of the appliance becoming electrilied.

In previous inventions one method adopted for the purpose of reducing the leakage to earth is to insert a length of tubing composed of non-electric conducting material and having a. restricted passage, that is to say a passage ot smaller diameter than the *ater' supply pipe which it connects with the heater. Another method is to insert a length ot non-electric conducting tubing contained within a metallic tube or sheath which serves as a protective covering. The first methodr has the objection that it renders the heater inctlicient for the purpose ot' heating comparatively large quantities of water as for inst-ance water for baths, because the restricted passage makes the process of heating very slow. The second method has the objection that although the metal sheathing may be electrically insulated there is always a risk of leakage where high tension current is employed, for example moisture between the non-electric conducting tube and its sheathing. This risk is entirely eliminated by our invention and moreover the ohmic resistance may be increased almost indelinitely by increasing the length ot the non--electric conducting tubing that is f inserted between the water supply pipe and the heater instead ot reducing the cross sectional area of the passage through the nonelectric conducting section of the water supply conduit.

The invention consists of a specially constructed heating element, preferably suspended within a vertical met-al cylinder,

OF THE NONSTORAGE TYPE.

734,791, and in Australia September 19, 1923.

the lower end of which is closed, while the upper end is provided with a suitable nonelectric conducting disc adapted to tit into the cylinder and make a water tight joint therewith. The cylinder is rigidly secured to a wooden frame and is covered by a suitably shaped metal cover which may if desired be provided with a hinged lid at the top. The cylindrical chamber is connected to a suitable water supply which is controlled b'y a two way cock adapted to connect the water supply to the heater or the heater' to the drain ott pipe, in which latter case the water would be cut oft'. lnterposed between the two way cock and the inlet opening to the cylindrical chamber is a glass or earthenware tube through which the water flows. The length of this tube will vary according to circui'i'istances, but any reasonable length may be obtained by ceiling it around the cylindrical chamber, where it would lie in the space between the cylindrical chamber and the metal cover by which it will be protected. The joints between the glass or earthenware tube and the metal pipe or fittings will be made by means of rubber or other suitable sockets that are secured by means of suitable clamping bands. The outlet for the heated water is situated near the top of the cylindrical chamber and is provided with a T connection, one arm of which extends upwardly, the other extending downwardly to a bath or other receptacle and being provided with a coc-k whereby when necessary the water may be diverted upwardly. Interposed between the T connection and the outlet opening of the cylindrical chamber is a glass or earthenwar'e tube coiled around the cylinder and connected in a similar manner to the glass or earthenware section of the supply pipe already described. The heating element is suspended on rods that act as electric leads to the tine wire or metal ribbon that is wound in a particular manner on a specially shaped bobbin that forms the heating element the upper ends of the leads being adjustably secured to the electric non-conducting disc that forms the upper end of the chamber. The special construction of the heating element makes it possible not only to use a very large quantity of fine resistance wire or metal ribbon,

but also ensures that practically the whole of the surface of such wire or ribbon is in direct contactY with the water within the heater, a factor which greatly adds to the efiiciency of the appliance owing the increased heating surface thereby obtained, means provided whereby the electric current is automatically switched on only after the water has risen within the heater to a point where the heating element is entirely submerged and if from any cause whatsoever the water supply should fail the electric current will be automatically switched off when. the level of the water within the heater recedes to a predetermined point above the uppermost part of the heating element thereby making it inipossible for the current to pas Uhrough theheating element unless the'latter is totally submerged.

lvlountedl upon the electric non-conducting disc which forms the upper end of the cylindrical chamber and within the metal casing is a `bracket adapted to carry an electromagnetically controlled switch, the electric supply and return leads are passed through an opening in the side of the outer casing and are electrically connected within the casing. rk pilot lainp will be installed in any convenient position near the heater and is suitably connected by leads to points within the casing. v

With the object of making the invention thoroughly understood a detailed description will now be given and reference will be made to the accompanying sheets of drawings in which y Fig. 1 is a perspective view of the heater secured to a wooden frame, the casing having been removedy and certain portions of the cylindricalcontainer being cut away in order to illustrate the parts within. A

Fig. 2 is a perspective viewl of the heater with the metal cover secured in position a section of the latter being removed to show aart of the glass or earthenware tube and the cylinder within. Y

Fig. 3 is a partial plan view of the end of theheating element bobbin.

Fig. l is a side view of Fig.

F ig. 4a is a view in perspective of a section ofthe heater unit showing the method of winding.

Fig. 51s a similar view to Fig. 1 with the addition that the method of wiring is shown in diagrammatic form.

Fig. G is a plan view of the bottom of the appliance with the outer casing removed.

Fig. 7 is a diagrammatic illustration of the manner in whichV the heating element is wound.

The water container 10 is preferably cylindrical in formation the lower end of which may be permanently closed in any suitable manner while the upper end is provided with annular metal rings '11, rigidly secured to the inner face of the cylindrical container in order to forni a seating upon which a disc 12' of slate or other suitable non-electric conducting material is secured so as to form a water tight joint therewith. The container 10 is rigidlylixed to a wooden frame 13 by means of the metal bands 14 or in any other convenient manner; `secured to the inlet opening 15 is a 'l' pipe connection 16 one of the horizontal arms of which will be plugged at 17, the other arm being connected to a glass or earthenware tube 18 by means of a rubber socket 19 that will be secured in position by means of the clamps 20. The glass or earthenware tube 1S may be of any required length according to the resistance it is desired to place between the container and the metallic water supply pipe 21 which will be supported by means of a bracket 22 that is fastened to the wooden frame 13 and connected to the outer end of the glass or earthenware tube 18a by means of a rubber socket 23 and clamps 24. The outlet opening 25 will be situated below the annular ring 11 and will be connected 'to one end of a glass or earthenware coiled tube 26, the other end being connected to a T pipe connection 27, the arms of whichV are connected to the pipe 28 the lower end being connected to a pipe 29 leading downwardly into the bat-h or other receptacle' and which is provided with a stop cock 3G whereby the heated water from the container may be diverted upwardly. The electrical connections are mounted upon the disc 12 and these and the cylindrical container with its glass or earthenware tubes will be covered by a metal cover 31 provided with flanges 32 by means of which it is secured to the frame 13 by the screws 33.

Vlit iin 'the metal cylindrical container 10 near its lower extremity a metalring is secured by screws or other suitable means so as to form an annular platform upon which the heating element is supported. The disc 12 is provided with four holes through which the upper ends of the electrical conducting rods 35, 36, 3T and 38 are passed and Athereby suspended by means of the nuts 39 that engage with the screw threaded ends of the rods. For the purpose of adjustment the rods 35, 36, 37 and 38 will be provided with collars 10 that support suspension springs 41 that surround the rods, theupper ends impinging on suitable washers L1-2 interposed between the springs and the underside of the disc 12.

The heating element is novel in construction and is bobbin like in formation. rlhe principle involved is that each turn of the resistance wire or metal ribbon is separate and is so wound upon the bobbinthat a very large percentage of each turn is entirely surrounded by air, that is to say a number of sections of each turn are stretched between two points on the bobbin and theeportions lying between those points are free to be entirely surrounded by the water to be heated when the heater is in use. There are a number' of methods by which a heating element could be constructed on this principle but we have found that the heating element described herein and illustrated in the drawings is simple to manufacture and is efiicient in its operation. It consists of two discs 43 and 44 of suitable non-conduct'- ing material such as slate, a tubular metal barrel 45, which acts as a distance piece, reinforcing discs 46 and 46, metal washers 47 interposed between the discs 43 and 44 and their respective reinforcing discs 46 and 46a. The discs 43 and 44, 4G and 46'Ll are axially bored to permit a bolt 4S to be passed through them and the tubular barrel in order to clamp the whole together by means of a washer 49`and nut 49n that engages with the threaded end of the bolt 48. The barrel 45 is'preierably electrically insulated by a glass tube 50.

The discs 43 and 44 are provided with three sets or sections ot' perforations 52 bored parallel with the axis ot the discs (Fig. 3) each set or section ci' pertorations consisting of a suitable number ot' lines er series oi perforations so arranged that slots 53 may be formed by a saw cut passing through each perforation in a line or series but in no case junctioning with another slot. The objectof these slots and pert'orations is to facilitate the operation of winding the resistance wire or metal ribbon longitudinally upon the bobbin. It will be seen that if the width of the slot 53 be less than that o'tf the diameter of the periorations and the slot be cut centrally through the perforations the latter will form channels or slots upon the side walls of the slots 53 and at right angles thereto thus providing a means whereby each turn of wire or metal ribbon may be retained in its position within the slot In winding the wire or metal ribbon upon the bobbin it will be passed along` the slot 53 to its position in the innermost slot therein, thence to a corresponding position on the disc at the other end of the bobbin across the outer face or a section of the disc lying between two adjacent channels 54, through that adjacent channel to a corresponding channel in the dise at the other end of the bobbin and so on until the bobbin is filled or a sufficient quantity of 'wire or drawing that the wire is threaded between the top and bottom discs, passing from a hole in the top disc to the corresponding hole in the bottom disc thence across to the next radial row and back to the top discv1 across the outside of the top disc to the next radial row thence through the disc and through the corresponding perforation in the bottom disc. In this manner, most ot the wire is exposed and is therefore in contact with the water. In the drawing, the tubular metal barrel 45, acting as a distance piece, has been omitted.

This construction enables a large number of spared turns to he wound upon the bobbin each complete turn forming two parallel lengths of the resistance wire or metal rib bon between the discs 43 and 44 and practically the entire length will be in direct contact with the water to be heated.

In order to obtain a still greater heating surface e'ach length of wire lying between the ends of the bobbin may be spirally formed.

The ends ot the resistance wire or metal ribbon on each section will be connected in delta formation as diagrammatically illustrated at Fig. 7 oit' the drawings or if desired they may be connected in star torniation and the leads 55, 56 and 57 electrically connected to the rods 235, 3G and 38 respectively.

Rigidly secured vertically upon the upper face of the disc 1Q in any suitable mauner is a metal standard 58 that carries a bracket 59 on which mounted an electromagnet G0 that is secured thereon in a vertical position and is provided with an armature (5l having a weight 62 integral with or rigidly secured at its lower end. The upper end of the armature 6l is securely fastened to a non-electric conducting plate (S3 that is provided with a pair ot.' metallic contacts 64. and 64a.. The bracket 59 is provided with a lug 65 to which is bolted a horizontal arm 66; upon this arm 66 is rigidly secured a plate 67 that carries a pair ot' contacts 68 and G9 with which the contacts 64 and G4 are adapted to contact when the electromagnet 60 is energized. The contacts 68 and (39 are electrically connected to the terminals 70 and 71.

In order to obviate any risk of danger arising from leakage of current to the casing 3l the latter is earthed by a wire 72 electrically connected to the casing and to the metallic water pipe 21.

A, B and C (Fig. 5) are the electric supply leads from a suitable electric supply, D being the return lead. These supply and return leads are electrically connected as follows- The lead A is connected to the switch terminal 71; the lead B is connected directly tothe top oi the rod 38; the lead C is connected to the switch terminal 70 thence by llt) the lead 7 3 through the winding of the` elect-romagnet 60 and lead 74 to the top of the rod 37 the return lead D through the terniinal and lead 76 to a conveniently sit-u ated pilot lamp 7 6a, the other lamp lead 77 being connected to the switch contact 6.4% and to the top of the rod 35. The switch contact 64 is electrically connected to the top of the rod 36 by the lead 7 8.

rihe two way cock 79 is provided with a plug 8O constructed and arranged that its movement is limited and when turned in one direction will open the water supply pipe to the heater at the same time closing the 'opening to the drain off pipe, but when turned in the oppositel direction will close the water supply pipe and open the drain off pipe so as to permit the water within the heater to drain into the bath or other receptacle.

In operating the heater the water' supply will be turned on through the cock 7 9 and when the water has risen within the container 10 to a point where it meets the lower end ot the adjustable rod 37 it will close an electric circuit through the lead rods 557-38,

lead 74C, electromagnet winding lead 73, terminal 7 0r and lead Upon the completion of this electric circuit the electromagnet will become energized, thereby raisingl the weighted armature 6l and closing .the switch contacts (M -64a and (5S-69 so as to close the remaining circuits through the heating element and the pilot lamp.

Should the wat-er supply fail from any cause whatsoever or if the water is turned oif, immediately the water level within the container recedes to a point where contact between the rod 37 and the water is broken the electromagnet will become de-energized and the weight 62 will cause the armature 6l to drop and break the contact between the switch contacts Git-64' and (5S-69 thereby opening the circuits through the heating element and the pilot lamp.

l/Ve claiml. In electric water heaters of the nonstorage type interposing a length of suitable non-electricrtubing between the water heating vessel and the metal water supply' and outflow pipes through which the water flows to and from such vessel, respectively, the supply section of such' non-conducting tubing having a bore at least equal in cross sectional area to that of the metal water supply pipe which it connects with the heater, the supply and outflow sections of the nonconducting tubing are entirely free from any metallic covering, an electric heating element in said water heater, a source of electric supply for energizing said heating element, and means controlled bythe water supply to said heater for supplying power to a portion of said heating element before energizing the entire element.

2. An electric water heater of the non# storage type characterized in that it is provided with an exposed heating element comprising a suitable bobbin upon lwhich is.

wound longitudinally ay plurality of lengths of high resistance conductors, means for maintaining aspace between each turn of such high resistance conductors for the purpose herein set forth, a source of electric supply for energizing said' heating element, and means controlled by the water supply to said heater for supplying power to a portion of said heating element before energizing the entire element.

3. An electric water heater of the nonstorage type characterized in that it is provided with an exposed heating element co1nprising a suitable bobbin upon which is woundl a plurality of lengths of high resistance conductors and means for maintaining a space completely around and between those parts of' each turn of the resistance conductors that lie between the points of the bobbin over which the conductors pass in winding in order that the whole surface of a very large percentage of the conductors will be in direct contact with the water to be heated, a source of electric supply for energizing said heating element, and means controlled by the water supply to said heater for supplying power to a portion of said heating element before energizing the. entire element.

il. In an electric water heater of the nonstorage type an exposed heating element as claimed in claim 3 characterized in that those portions of the resistance conductors of which the whole surface is in direct contact with the water to be heated are formed into spirals for the purpose of obtaining a still greater area of heating surface.

5. An improved water heater of the non storage type comprising a container an eX- posed element within the container, a water inlet opening at or near the bottom of the container, a water outlet opening at or near the top of the container, and a suitable length of non-electric conducting tube connected to and interposed between the inlet opening and the metal water supply pipe,the outlet opening and metal delivery pipe respectiyely, a source of electric supply for energizing said exposed element, and means controlled by the water supply to said heater ror supplying power to a portion of said exposed element before energizing the entire' of the bobbin whereby lengths of high resistance conductors are wound longitudinally upon the bobbin7 means for maintaining a space between each turn of the high resis- 5 tance conductors, a, source of electric supply for energizing said heat-ing element, and means controlled by the Water supply to Said heater for supplying power lo a portion of said heating element before energizing the entire element.

In testimony whereof, We have signed our names to this Specification.

WALTER STUBBS. HORACE STUBBS. 

